During drilling and upon completion and production of an oil and/or gas wellbore, a workover and/or completion tubular string can be installed in the wellbore to allow for production of oil and/or gas from the well. Current trends involve the production of oil and/or gas from deeper wellbores with more hostile operating environments. In order to produce the oil and/or gas from the wellbore, the wellbore is typically perforated to provide one or more fluid pathways through a casing lining the wellbore to the subterranean formation containing the oil and/or gas.
During the process of perforating an oil or gas well, a perforating gun assembly can be lowered into and positioned within the wellbore. A typical perforating gun assembly consists of one or more perforating guns, as well as possibly some spacer sections. If the zone to be perforated is longer than the amount which can be perforated with a single gun, then multiple perforating guns are connected together to create a perforating gun assembly of the desired length. Further, if there is more than one zone to be perforated and there is some distance between the zones to be perforated, spacer sections may be inserted between the guns in the gun assembly. These spacer sections have detonation cord running from end to end, to transfer the detonation through each spacer section to the next component. In order for the explosive transfer to occur from one section to the next in the gun assembly, an explosive transfer system may be employed.